Wavelength division multiplexing (WDM) of optical beams is presently being used to increase the rate of transmission of information through an optical fiber. These multi-wavelength optical beams provide information by a plurality of signal components, also referred to as optical channels. Each channel is defined by a unique wavelength of light. These beams are multiplexed together and transmitted through a communication link of an optical network. The optical beam comprises the main signal transmission carrier (or "line" in electrical parlance).
Present day telecommunication systems are point to point systems where capacity can be increased by just an increase in the bit rate. Wavelength division multiplex systems (WDM) in which a number of signals propagate through a single fiber allow the increase of capacity of the single fiber or the total bit rate by adding different colors of light (channels). With links presently in service, signals are added only at the beginning of the link. It would be desirable to dynamically reconfigure the bandwidth of a network to meet customer demand by re routing of channels as needed.
Mechanical switches and silica-on-silicon waveguides using thermal switching have been developed for use in dynamically reconfiguring signal channels, but suffer from their broadband nature. Arrays of these switches can be combined with traditional demultiplexers and multiplexers to form a wavelength selective add/drop moduler for WDM links. This solution is unattractive from both performance and cost standpoints. Alternate electro-optic solution, such as an AOTF switches, are highly desirable, however, the required devices are not presently available. To date, suitable add/drop devices simply do not yet exist.
It would be desirable to have a wavelength division multiplex optical network with an apparatus capable of adding and/or dropping signal channels so that the network is dynamically reconfigurable. The present invention is drawn toward such a network and apparatus.